1. Field of the Invention
The invention generally relates to the prevention of ischemia/reperfusion injury. In particular, the invention provides a method of preventing ischemia/reperfusion injury by administering a phosphodiesterase-5 (PDE5) inhibitor such as sildenafil.
2. Background of the Invention
Heart disease remains a leading cause of morbidity and mortality in the United States, affecting approximately 5–6 million Americans, particularly those age 65 and older. In 1995, an estimated $3.4 billion dollars was spent by Medicare for the treatment of heart disease. A continually aging population is expected to result in an increased number of people afflicted with heart-related conditions, requiring costly long-term medical management with an unpredictable affect on quality of life.
Surgical intervention for the treatment of heart disease is widely practiced. In particular, procedures such as coronary bypass and angioplasty are now carried out on a routine basis. However, they are not without inherent risks and the potential for further damage to an already diseased heart. During heart surgery, the heart itself must be temporarily isolated from the circulatory system, and then reperfused with blood following completion of the surgery. This isolation procedure entails the possibility of further damage to the heart and may defeat the purpose of or lessen the benefit of the surgical procedure.
While adenosine is known to cause preconditioning and protection of the heart under these circumstances, it has been determined that the clinical effects are not as promising as those initially reported by experimental studies (Vinten-Johansen et al. 2003). Thus, there is an ongoing need for the discovery of preconditioning agents that afford protection to cells, tissues and organs during periods of potential ischemic injury.